I think I've worked out why some people are finding it so hard to include comics in forum threads.
When you set up a new account, it defaults to not showing comics in the forums, doesn't it? So all these new people don't actually realise you CAN post comics in the forums. They just see a text link, and so we get loads of half assed attempts at putting links to comics pages, and \2 everywhere etc.
Might it be worth having comics displaying in the forums defaulting to on for new accounts. Maybe make it clear in the signup email or faq or something that this can easily be switched off from the "edit account" page.
That way, when people sign up, they'll see comics everywhere and think "Cool! How do I do that?" and then maybe, just maybe, they'll find out the proper way of inserting the ubb code.